how to fix a P0301 misfire code in my BMW 3 Series F30/F31 (2012-2019)?

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to avoid electrical shorts.

Tools Required:

• OBD-II scanner
• Socket set
• Torque wrench
• Compression tester
• Multimeter
• Fuel injector cleaner (if necessary)

2. Replace Spark Plug

1. Remove the engine cover if applicable.
2. Locate the spark plug for cylinder 1.
3. Use a spark plug socket to remove the old spark plug.
4. Check the gap on the new spark plug and adjust if necessary (typically around 0.030 inches).
5. Install the new spark plug hand-tight, then torque to manufacturer specifications (usually around 22 ft-lbs).
6. Reinstall the engine cover.

3. Inspect/Replace Ignition Coil

1. Disconnect the electrical connector from the ignition coil on cylinder 1.
2. Remove the bolt securing the ignition coil using a socket.
3. Pull the ignition coil out of the spark plug well.
4. Inspect the ignition coil for cracks or damage; replace if necessary.
5. Install the new ignition coil by inserting it into place and securing it with the bolt. Reconnect the electrical connector.

4. Conduct Compression Test

1. Remove the spark plug from cylinder 1 if it hasn’t been removed already.
2. Insert the compression tester into the spark plug hole.
3. Crank the engine for a few seconds and record the reading.
4. If the compression is below manufacturer specifications, further diagnosis is needed (potential valve or piston issues).

5. Check Fuel Injector

1. Use a multimeter to check the resistance of the fuel injector on cylinder 1; compare to specifications.
2. If faulty, remove the fuel rail and replace the injector.
3. Clean the fuel injector using a fuel injector cleaner if it is operational but clogged.